Vehicles driven by internal combustion engines generally employ intake system sensors including, but not limited to, a throttle position sensor (TPS), a mass airflow (MAF) sensor and a manifold absolute pressure (MAP) sensor. An engine control system implements an electronic throttle control (ETC) system that regulates engine torque output based on a throttle position signal, a MAF signal and a MAP signal. The engine control system can also regulate engine torque output using spark advance/retard, cam phasing and/or regulating fuel supply to the cylinders.
The engine control system executes an ETC diagnostic system that determines whether the TPS, MAF and MAP sensors are functioning properly and are providing accurate readings. The ETC diagnostic system uses MAP and MAF residuals or error values to determine proper sensor function. In traditional engine control systems, the MAP and MAF errors can not be calibrated to meet ETC security requirements without resulting in false failures. Additional system redundancy is required to ensure that the failures intended to be detected by the ETC diagnostic do not exceed the ETC security probability of occurrence metrics. The additional redundancy increases vehicle production costs and false failures increase warranty costs.